Wheel assembly for an irrigation system

ABSTRACT

A wheel assembly for traversing a path along a ground surface having a layer of soil, the wheel assembly comprising a central support and an airless flexible covering mounted on the central support and having a plurality of rigid sections and a plurality of flexible sections. The outwardly protruding spokes urge the rigid sections into the layer of soil when the rigid sections contact the ground surface. The flexible sections include a set of traction lugs for gripping peaks of a corrugated pattern in the ground surface for improved traction.

RELATED APPLICATIONS

The present application is a continuation application and claimspriority of a co-pending application titled “WHEEL ASSEMBLY FOR ANIRRIGATION SYSTEM”, Ser. No. 14/161,151, filed Jan. 22, 2014, thecontent of which is hereby incorporated by reference in its entirety.

BACKGROUND

The present invention relates to wheel assemblies for movableagricultural irrigation systems.

Movable agricultural irrigation systems such as center-pivot and linearsystems are commonly used to irrigate large fields and typically includeseveral irrigation spans mounted on movable support towers. Each movablesupport tower includes two wheel assemblies configured to traverse apath along the ground for moving the irrigation spans across the fields.After multiple passes of the irrigation system, the path often developsdeep ruts in which the wheels of the wheel assemblies can become stuck.The path can be repaired by filling the ruts with soil or othermaterial, but this requires a substantial amount of material, is timeconsuming, and is difficult to do without damaging crops in the process.Alternatively, the wheels of the wheel assemblies can be replaced withwider wheels for traversing un-worn ground adjacent to the path, butthis requires an additional set of wheels and further damages the path.Moreover, this solution does not work if the current set of wheels isthe widest available. Ruts can also be minimized by shifting the centerpivot point by a few feet so that the wheel assemblies create a newpath, but this results in the destruction of additional crops and maycause the wheel assemblies to become stuck or misaligned when crossingover the worn path. Also, this requires the installation of additionalpipe and electrical center-pivot components.

SUMMARY

The present invention solves the above-described problems and provides adistinct advance in the art of wheel assemblies for irrigation systems.More particularly, the present invention provides a wheel assembly thatcauses less wear on a field or other area to be irrigated while stillproviding excellent traction.

A wheel assembly constructed in accordance with an embodiment of theinvention broadly comprises a wheel having a set of outwardly protrudingspokes that define a set of recesses therebetween and a tire, track, orother covering mounted on the wheel. The covering has a set of rigidsections that are urged by the outwardly protruding spokes of the wheelinto a layer of soil on the ground and a set of flexible sections thatflex inwardly towards the recesses between the spokes. The covering alsohas a set of primary and secondary traction lugs on its outer surface.Each primary traction lug is aligned with a middle of a flexible sectionof the covering and is taller than the secondary traction lugs. Thesecondary traction lugs are positioned near ends of the flexiblesections of the covering and are spaced a greater distance from theadjacent secondary traction lug than from the adjacent primary tractionlug.

The wheel and the covering cooperatively form a series of alternatingpeaks and valleys in the soil in a generally corrugated path. Duringsubsequent passes of the irrigation system, the rigid and flexiblesections of the covering line up with the previously created peaks andvalleys in the soil to greatly improve the traction of the wheelassembly. Moreover, the wheel assembly urges some of the soil from thevalleys to the peaks instead of towards side margins of the path toreduce rut formation. As a flexible section is urged into a recess, itsprimary traction lug grips the top of the peak. The secondary tractionlugs, being positioned on either side of the primary traction lug on theflexible section, are turned slightly inward towards the primarytraction lug and grip the sides of the peak.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the present invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of an irrigation system support tower onwhich wheel assemblies constructed in accordance with embodiments of theinvention may be mounted;

FIG. 2 is an elevational view of the wheel assemblies of FIG. 1 shownforming a generally corrugated track on a ground surface;

FIG. 3 is an enlarged, fragmentary elevational view of one of the wheelassemblies of FIG. 2; and

FIG. 4 is an enlarged, fragmentary elevational view of one of the wheelassemblies of FIG. 2.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following detailed description of the invention references theaccompanying drawings that illustrate specific embodiments in which theinvention can be practiced. The embodiments are intended to describeaspects of the invention in sufficient detail to enable those skilled inthe art to practice the invention. Other embodiments can be utilized andchanges can be made without departing from the scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment”, “an embodiment”, or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment”, “an embodiment”, or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the present technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Turning now to the drawing figures, and particularly FIGS. 1-4, amovable irrigation support structure 10 with first and second wheelassemblies 12 a,b constructed in accordance with embodiments of theinvention is illustrated. The movable support structure 10 is part of anagricultural irrigation system such as a center-pivot or linearirrigation system, a planter, a sprayer, or any other agriculturalimplement. The movable support structure 10 may join and support movablespans or extensions of the irrigation system that are used to irrigate afield or other area.

The wheel assemblies 12 a,b of the present invention are mounted nearopposite ends of the movable support structure 10. Because the wheelassemblies 12 a,b are essentially identical, only the first wheelassembly 12 a will be described in detail.

As best shown in FIG. 2, the first wheel assembly 12 a broadly includesa central support 14 configured to be mounted on a central hub 16 of themovable support structure 10 and a tire, track, or other flexiblecovering 18 mounted on the central support 14.

The central support 14 may be a wheel, a sprocket, a cog, or a similarcomponent, The central support 14 is rotatably coupled to the movablesupport structure 10 via the central hub 16 and may be attached to thecentral support 14 via holes that receive threaded shafts of the centralhub 16. The central support 14 includes a set of approximately 10outwardly protruding spokes (e.g., outwardly protruding spokes 20 a-c)configured to engage the airless flexible covering and a set of recesses(e.g., recesses 22 a-c) between the outwardly protruding spokesconfigured to receive the flexible sections of the airless flexiblecovering 18.

Because the outwardly protruding spokes 20 a-c are essentiallyidentical, only the outwardly protruding spoke 20 a will be described.The outwardly protruding spoke 20 a includes prongs 24 a,b and forms a Uor V shape, as shown in FIG. 3. The prongs 24 a,b are configured todistribute compression forces to the central support 14 for decreasingmaximum point loads when the outwardly protruding spoke 20 a engages theground surface 26. The outwardly protruding spoke 20 a presentsgradually curved outer edges configured to prevent the airless flexiblecovering 18 from developing folds when contacting the ground surface 26.The outwardly protruding spoke 20 a may be attached to the centralsupport 14 via bolts, hinges, or other fasteners and may be partially orcompletely detachable or retractable for mounting the airless flexiblecovering 18 onto the central support 14.

The recesses 22 a-c are concave areas between the outwardly protrudingspokes 20 a-c and each are configured to receive a flexible section ofthe airless flexible covering 18 (described below) when engaging theground surface 26, as best shown in FIG. 4.

The airless flexible covering 18 is provided for engaging the groundsurface 28, for providing additional traction, and for protecting thecentral support 14, as shown in FIGS. 3 and 4. The airless flexiblecovering 18 may be a tire, a belt, or a linked track and is formed ofmolded rubber or other relatively pliable high friction material. Theairless flexible covering 18 may be approximately 12.5 inches wide andincludes a set of rigid sections (e.g., rigid section 28) configured toalign with the outwardly protruding spokes 20 a-c, a set of flexiblesections (e.g., flexible section 30) configured to align with therecesses 22 a-c, and an outer surface 32 configured to contact theground surface 26, as described below.

Because the rigid sections are essentially identical, only the rigidsection 28 will be described. The rigid section 28 includes an inwardlyfacing mounting boss 34 for receiving the outwardly protruding spoke 20a. The mounting boss 34 includes a gradually curving contour such that athickness of the airless flexible covering 18 increases towards themounting boss 34 for reducing fatigue near the mounting boss 34. Themounting boss 34 is configured to maintain a rotational alignment of theairless flexible covering 18 with the central support 14 and to preventthe airless flexible covering 18 from shifting laterally with respect tothe central support 14.

The flexible sections are intermediate the rigid sections. Because theflexible sections are essentially identical, only the flexible section30 will be described. The flexible section 30 is aligned with a recess22 a and is urged into the recess 22 a when engaging the ground surface26, as best shown in FIG. 4. When not engaging the ground surface 26,the flexible section 30 may revert to an outwardly arcuate shape.

The outer surface 32 is configured to contact the ground surface 26 andis substantially flat from its left edge to its right edge. The outersurface 32 includes a plurality of primary traction lugs 36 a-c and aplurality of secondary traction lugs 38 a-c.

Because the primary traction lugs 36 a-c are essentially identical, onlythe primary traction lug 36 a will be described. The primary tractionlug 36 a is aligned with the middle of the flexible section 30 and has aheight greater than the secondary traction lugs 38 a-c, as best shown inFIG. 4. The primary traction lug 36 a may have an elongated shape andmay be widest at its middle point and narrowest at its ends (FIG. 1).

The secondary traction lugs 38 a-c are also essentially identical, soonly the secondary traction lug 38 a will be described. The secondarytraction lug 38 a is positioned between the middle of the flexiblesection 30 and the middle of the adjacent rigid section 28, as bestshown in FIG. 4. The secondary traction lug 38 a is spaced a greaterdistance from the adjacent secondary traction lug 38 b than from theadjacent primary traction lug 36 a. The secondary traction lug 38 a mayhave an elongated shape and may be widest at its middle point andnarrowest at its ends (FIG. 1).

Turning again to FIG. 2, the second wheel assembly 12 b includes asecond central support 40 configured to be mounted on a second centralhub 42 of the movable support structure 10 and a second airless flexiblecovering 44 mounted on the second central support 40.

The second central support 40 is essentially identical to the firstcentral support 14, and the second airless flexible covering 44 isessentially identical to the first airless flexible covering 18. Thesecond central support 40 is spaced from and aligned with the firstcentral support 14 so that the second central support 40 traverses apath along the ground surface 26 after the first central support 14.

The above-described wheel assemblies 12 a,b provide several advantagesover conventional wheels. For example, the wheel assemblies 12 a,bcreate a pattern in the ground that improves wheel traction onsubsequent passes of the irrigation system. The wheel assemblies 12 a,balso maintain a rotational alignment with the pattern and rotationallyrealign themselves if they become rotationally misaligned with thepattern. Moreover, the wheel assemblies 12 a,b create less wear on thepath traversed by the movable support structure 10 and minimize rutformation in the path.

Specifically, as shown in FIGS. 2-4, the above-described first wheelassembly 12 a forms alternating peaks 46 a-c and valleys 48 a-c in agenerally corrugated track 50 in a layer of compliant soil 52 on theground surface 26 along the path traversed by the movable supportstructure 10. As a portion of the wheel assembly 12 a engages the groundsurface 26, the outwardly protruding spokes 20 a-c of the centralsupport 14 urge the rigid sections of the airless flexible covering 18into the soil 52 and form the valleys 48 a-c of the corrugated track 50by urging some of the soil 52 forwards or backwards along the path, asbest shown in FIG. 3. The recesses 22 a-c of the central support 14receive the flexible sections of the airless flexible covering 18 andform the peaks 46 a-c between the valleys 48 a-c with the soil 52 urgedout of the valleys 48 a-c, as best shown in FIG. 4.

In addition, the primary and secondary traction lugs 36 a-c and 38 a-cof the airless flexible covering 18 grip the peaks 46 a-c of thecorrugated track 50 as the flexible sections of the airless flexiblecovering 18 are urged into the recesses 22 a-c. For example, the primarytraction lug 36 a grips the top of the peak 46 a of the corrugated track50, and the secondary traction lugs 38 a,b, being positioned between themiddle and ends of the flexible section 30, are turned slightly inwardtowards the adjacent primary traction lug 36 a and grip the sides of thepeak 46 a, thus improving traction.

Features of the second wheel assembly 12 b engage common engagementpoints of the corrugated track 50 with features of the first wheelassembly 12 a when the second wheel assembly 12 b is rotationallysynchronized with the first wheel assembly 12 a, as shown in FIG. 2.That is, outwardly protruding spokes of the second central support 40are urged into the valleys 48 a-c of the corrugated track 50, andrecesses of the second central support 40 meet the peaks 46 a-c createdor previously traversed by the outwardly protruding spokes 20 a-c andrecesses 22 a-c of the first central support 14. In addition, primaryand secondary traction lugs of the second airless flexible 44 coveringgrip the previously traversed peaks 46 a-c. This synchronizationreinforces the corrugated track 50 and further improves traction and isparticularly beneficial for when the layer of soil 52 is compliant, suchas after a rainfall or in muddy circumstances.

Features of the second wheel assembly 12 b engage different engagementpoints of the corrugated track 50 than features of the first wheelassembly 12 a when the second wheel assembly 12 b is unsynchronized (oroffset) with the first wheel assembly 12 a. That is, outwardlyprotruding spokes of the second central support 40 meet the peaks 46 a-cof the corrugated track 50, and recesses of the second central support40 meet the valleys 48 a-c created or previously traversed by therecesses 22 a-c and outwardly protruding spokes 20 a-c of the firstcentral support 14. This offset alignment reduces the corrugation effectand may be beneficial when the layer of soil 52 is less compliant, suchas during a dry period,

When the wheel assemblies 12 a,b are rotationally synchronized, they maypositively maintain a rotational alignment with the corrugated track 50.For example, the outwardly protruding spokes 20 a-c of the first wheelassembly 12 a maintain a rotational alignment of the first wheelassembly 12 a with the corrugated track 50 by repeatedly engaging thevalleys 48 a-c of the corrugated track 50 during subsequent passes alongthe path. This helps the wheel assemblies 12 a,b preserve the corrugatedtrack 50 and maintain improved traction as the movable support structure10 traverses the path.

The wheel assemblies 12 a,b also rotationally realign themselves if theybecome rotationally misaligned with the corrugated track 50. Forexample, the rigid section 28 of the airless flexible covering 18, beingsubstantially exposed to the ground surface 26 by not having tractionlugs located on its outer surface area, will slip against the peak 46 aof the corrugated track 50 until the primary and the secondary tractionlugs 36 a, 38 a,b begin to grip the peak 46 a and the outwardlyprotruding spoke 20 a engages the valley 48 a if the wheel assembly 12 abecomes rotationally misaligned with the corrugated track 50. Again,this helps the wheel assemblies 12 a,b preserve the corrugated track 50and maintain improved traction as the movable support structure 10traverses the path.

Moreover, the wheel assemblies 12 a,b retain soil 52 in the pathtraversed by the movable support structure 10. For example, thesubstantially flat outer surface 34 of the first wheel assembly 12 aengages the soil 52 evenly from its left edge to its right edge, whichprevents much of the soil 52 from being urged to side margins of thecorrugated track 50. This helps the wheel assemblies 12 a,b create lesswear on the path and minimize rut formation therein.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims.

Having thus described various embodiments of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

What is claimed is:
 1. An airless flexible covering configured to bemounted on a central support of a wheel assembly for traversing a pathalong a ground surface having a layer of soil, the airless flexiblecovering comprising: an outer surface; an inner surface opposite theouter surface; a plurality of rigid sections each including an inwardlyfacing mounting boss on the inner surface for aligning with and engagingoutwardly protruding spokes of the central support; a plurality offlexible sections for aligning with recesses of the central support; anda plurality of primary traction lugs and a plurality of secondarytraction lugs disposed on the outer surface, each primary traction lugbeing configured to be substantially aligned with a center of one of therecesses, each secondary traction lug being spaced from the primarytraction lugs and spaced from adjacent secondary traction lugs a greaterdistance than from the primary traction lugs, the rigid sections beingconfigured to be urged into the layer of soil by the outwardlyprotruding spokes of the central support when the rigid sections contactthe ground surface and the flexible sections being configured to flexinwardly towards the recesses when the flexible sections contact theground surface so that the rigid sections and the flexible sectionscooperatively form a corrugated track in the ground surface withouturging the soil to side margins of the airless flexible covering, thecorrugated track having a plurality of valleys formed by the rigidsections and a plurality of spaced peaks formed by the flexiblesections, and the primary traction lugs and the secondary traction lugsbeing configured to grip the peaks when the flexible sections contactthe ground surface.
 2. The airless flexible covering of claim 1, whereinthe primary traction lugs define a height greater than a height of thesecondary traction lugs for maintaining the grip on the peaks.
 3. Theairless flexible covering of claim 1, wherein each primary traction lugis adjacent at least one of the secondary traction lugs, each secondarytraction lug being configured to turn slightly inward towards anadjacent primary traction lug for gripping a side of one of the peakswhen the flexible section is urged into the recess.
 4. The airlessflexible covering of claim 1, wherein one of the primary traction lugsand two of the secondary traction lugs are positioned between each rigidsection.
 5. The airless flexible covering of claim 1, wherein theairless flexible covering is configured to automatically rotationallyalign itself with the corrugated track in the ground surface by slippingwith the central support until the rigid sections of the airlessflexible covering engage the valleys of the corrugated track.
 6. Theairless flexible covering of claim 5, wherein the rigid sections of theairless flexible covering are configured to retain the rotationalalignment of the airless flexible covering with the corrugated track byrepeatedly engaging the valleys of the corrugated track.
 7. The airlessflexible covering of claim 1, wherein each primary traction lug and eachsecondary traction lug has a middle section having a maximum width andtwo opposing ends having a minimum width.
 8. The airless flexiblecovering of claim 1, wherein the mounting bosses each include a V-shapedchannel for receiving one of the outwardly protruding spokes of thecentral support.
 9. The airless flexible covering of claim 1, whereinthe mounting bosses include a gradually curving contour for reducingwear on the airless flexible covering.
 10. The airless flexible coveringof claim 1, wherein a thickness of the airless flexible coveringincreases towards the mounting bosses for reducing wear near themounting bosses.
 11. The airless flexible covering of claim 1, whereinthe airless flexible covering includes ten mounting bosses.
 12. Theairless flexible covering of claim 1, wherein the airless flexiblecovering has a width of 12.5 inches.
 13. The airless flexible coveringof claim 1, wherein the airless flexible covering is formed of moldedrubber.
 14. An airless flexible tire configured to be mounted on acentral support of a wheel assembly for traversing a path along a groundsurface having a layer of soil, the airless flexible tire comprising: anouter surface; an inner surface opposite the outer surface; a pluralityof rigid sections each including an inwardly facing mounting boss on theinner surface for aligning with and engaging outwardly protruding spokesof the central support; a plurality of flexible sections for aligningwith recesses of the central support; and a plurality of primarytraction lugs and a plurality of secondary traction lugs disposed on theouter surface, each primary traction lug being configured to besubstantially aligned with a center of one of the recesses, eachsecondary traction lug being spaced from the primary traction lugs andspaced from adjacent secondary traction lugs a greater distance thanfrom the primary traction lugs, the rigid sections being configured tobe urged into the layer of soil by the outwardly protruding spokes ofthe central support when the rigid sections contact the ground surfaceand the flexible sections being configured to flex inwardly towards therecesses when the flexible sections contact the ground surface so thatthe rigid sections and the flexible sections cooperatively form acorrugated track in the ground surface without urging the soil to sidemargins of the airless flexible tire, the corrugated track having aplurality of valleys formed by the rigid sections and a plurality ofspaced peaks formed by the flexible sections, and the primary tractionlugs and the secondary traction lugs being configured to grip the peakswhen the flexible sections contact the ground surface.
 15. The airlessflexible tire of claim 14, wherein the primary traction lugs define aheight greater than a height of the secondary traction lugs formaintaining the grip on the peaks.
 16. The airless flexible tire ofclaim 14, wherein each primary traction lug is adjacent at least one ofthe secondary traction lugs, each secondary traction lug beingconfigured to turn slightly inward towards an adjacent primary tractionlug for gripping a side of one of the peaks when the flexible section isurged into the recess.
 17. The airless flexible tire of claim 14,wherein one of the primary traction lugs and two of the secondarytraction lugs are positioned between each rigid section.
 18. The airlessflexible tire of claim 14, wherein each primary traction lug and eachsecondary traction lug have a middle section having a maximum width andtwo opposing ends having a minimum width.
 19. The airless flexible tireof claim 14, wherein the airless flexible tire is formed of moldedrubber.
 20. An airless flexible covering configured to be mounted on acentral support of a wheel assembly for traversing a path along a groundsurface having a layer of soil, the airless flexible coveringcomprising: an outer surface; an inner surface opposite the outersurface; a plurality of rigid sections each including an inwardly facingmounting boss on the inner surface for aligning with and engagingoutwardly protruding spokes of the central support, each mounting bossincluding a V-shaped channel for receiving one of the outwardlyprotruding spokes of the central support and a gradually curving contourfor reducing wear on the mounting bosses; a plurality of flexiblesections for aligning with recesses of the central support; and aplurality of primary traction lugs and a plurality of secondary tractionlugs disposed on the outer surface, each primary traction lug beingconfigured to be substantially aligned with a center of one of therecesses, each secondary traction lug being spaced from the primarytraction lugs and spaced from adjacent secondary traction lugs a greaterdistance than from the primary traction lugs, the primary traction lugshaving a height greater than a height of the secondary traction lugs;the rigid sections being configured to be urged into the layer of soilby the outwardly protruding spokes of the central support when the rigidsections contact the ground surface and the flexible sections beingconfigured to flex inwardly towards the recesses when the flexiblesections contact the ground surface so that the rigid sections and theflexible sections cooperatively form a corrugated track in the groundsurface without urging the soil to side margins of the airless flexiblecovering, the corrugated track having a plurality of valleys formed bythe rigid sections and a plurality of spaced peaks formed by theflexible sections, and the primary traction lugs and the secondarytraction lugs being configured to grip the peaks when the flexiblesections contact the ground surface, the rigid sections being configuredto retain the rotational alignment of the airless flexible covering withthe corrugated track by repeatedly engaging the valleys of thecorrugated track, the airless flexible covering being configured toautomatically rotationally align itself with the corrugated track in theground surface by slipping with the central support until the rigidsections of the airless flexible covering engage the valleys of thecorrugated track.